Rocky Mountain Forests
It is stirring to stand at the feet of the Rocky Mountains and look upward and far away over the broken strata that pile and terrace higher and higher, until, at a distance of twenty-five or thirty miles, they stand a shattered and snowy horizon against the blue. The view is an inspiring one from the base, but it gives no idea that this mountain array is a magnificent wild hanging-garden. Across the terraced and verdure-plumed garden the eternal snows send their clear and constant streams, to leap in white cascades between crowning crags and pines. Upon the upper slopes of this garden are many mirrored lakes, ferny, flowery glens, purple forests, and crag-piled meadows.
If any one were to start at the foothills in Colorado, where one of the clear streams comes sweeping out of the mountains to go quietly across the wide, wide plains, and from this starting-place climb to the crest of this terraced land of
crags, pines, ferns, and flowers, he would, in so doing, go through many life-zones and see numerous standing and moving life-forms, all struggling, yet seemingly all contented with life and the scenes wherein they live and struggle.
The broad-leaf cottonwood, which has accompanied the streams across the plains, stops at the foothills, and along the river in the foothills the narrow-leaf cottonwood (Populus angustifolia) crowds the water's edge, here and there mingling with red-fruited hawthorns and wild plums (Prunus Americana). A short distance from the stream the sumac stands brilliant in the autumn, and a little farther away are clumps of greasewood and sagebrush and an occasional spread of juniper. Here and there are some forlorn-looking red cedars and a widely scattered sprinkling of stunted yellow pines (Pinus scopulorum).
At an altitude of six thousand feet the yellow pine acquires true tree dignity and begins to mass itself into forests. When seen from a distance its appearance suggests the oak. It seems a trifle rigid, appears ready to meet emergencies, has a look of the heroic, and carries more character than any
other tree on the Rockies. Though a slender and small-limbed tree in youth, after forty or fifty years it changes slowly and becomes stocky, strong-limbed, and rounded at the top. Lightning, wind, and snow break or distort its upper limbs so that most of these veteran pines show a picturesquely broken top, with a towering dead limb or two among the green ones. Its needles are in bundles of both twos and threes, and they vary from three to eight inches in length. The tree is rich in resin, and a walk through its groves on an autumn day, when the sun shines bright on its clean golden columns and brings out its aroma, is a walk full of contentment and charm. The bark is fluted and blackish-gray in youth, and it breaks up into irregular plates, which on old trees frequently are five inches or more in thickness. This bark gives the tree excellent fire-protection.
The yellow pine is one of the best fire-fighters and lives long. I have seen many of the pines that were from sixty to ninety feet high, with a diameter of from three to five feet. They were aged from two hundred and fifty to six hundred years. Most of the old ones have lived through several
fires. I dissected a fallen veteran that grew on the St. Vrain watershed, at an altitude of eight thousand feet, that was eighty-five feet high and fifty-one inches in diameter five feet from the ground. It showed six hundred and seventy-nine annual rings. During the first three hundred years of its life it averaged an inch of diameter growth every ten years. It had been through many forest fires and showed large fire-scars. One of these it received at the age of three hundred and thirty-nine years. It carried another scar which it received two hundred and sixteen years before its death; another which it received in 1830; and a fourth which it received fourteen years before it blew over in the autumn of 1892. All of these fire-scars were on the same quarter of the tree. All were on that part of the tree which overlooked the down-sloping hillside.
Forest fires, where there is opportunity, sweep up the mountain-side against the lower side of the trees. The lower side is thus often scarred while the opposite side is scarcely injured; but wind blowing down the gulch at the time of each fire may have directed the flames against the lower side